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Dehydration kinetics of talc at 1 barExperimental results on the dehydration kinetics of talc, which is likely to be a major potential resource for water and hydrogen in carbonaceous chondrites, is presented. The rate of dehydration of an essentially pure Mg-end member natural talc, (Mg(.99)Fe(.01))3Si4O10(OH)2, was studied by measuring in situ weight change under isothermal condition at 1 bar as a function of time in the temperature range 775 to 985 C. The grain size of the starting material was 0.7 to 1 micron. It was found that the data up to 50 to 60 percent dehydration can be fitted by an equation of the form alpha = exp(-Kt(exp n)), where alpha is the weight fraction of talc remaining, K is a rate constant and n is a numerical constant for a given temperature. For any set of isothermal data, there is a major change in the value of n for larger dehydration. For up to approximately 50 percent dehydration, all rate constants can be described by an Arrheniun relation with an activation energy of 432 (+/- 30) kJ/mol; n has a nearly constant value of 0.54 between 775 and 875 C, but increases almost linearly according to n = -10.77 + 0.012T C at T greater than or equal to 875 C.
Document ID
19910015065
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Ganguly, J.
(Arizona Univ. Tucson, AZ, United States)
Bose, K.
(Arizona Univ. Tucson, AZ, United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1991
Publication Information
Publication: NASA Space Engineering Research Center for Utilization of Local Planetary Resources
Subject Category
Inorganic And Physical Chemistry
Accession Number
91N24378
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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